In public speaking, many people have little tips and tricks to help with being nervous. They may tell you to picture everyone naked (does anyone actually *do* that??), or to focus on a single person, make eye contact, and pretend like you are speaking only to them.
For interviewing, I found a way of looking at the interview that seemed to really help alleviate my nervousness before and during an interview: I pretended like I was just chatting with someone I had met at a conference.
I went to Agile 2009 in August, and I met a great many people that were in all kinds of different positions. Some were testers, some were developers, some were coaches, some were Ux experts. Some were consultants, some worked for very large companies, some very small. The range of experiences and situations was pretty big. I found that conversations were easy to get into with every single person I met. I'd ask a bit about where they worked and what they did, and what they were hoping to get out of the conference. I'd tell them a bit about me and what I was hoping to get out of the conference, too.
Sometimes someone would say something about an issue they were trying to solve that I had experience with, and I would be able to share some of my experience with them. Of course, this was a two way street, and I got a lot of great advice too. The point is that I did this enough times that in just a few short days it became pretty natural. If you've been to a large professional gathering, I'd guess that you've done much of the same thing.
So the next time I found myself on the interviewee side of the table, I told myself that I was just talking to another person I had met at a conference. I think that this idea addresses two main points of an interview: it helps me to learn about the company I am interviewing for (after all, an interview *is* (or should be) two-sided), *and* it helps them to get insight into what *I* can do for their team should they hire me.
When I ask them about what they do, I learn some more than just a job description provides about the company, the team, and the role. I can ask specific questions, like what a day in the life of this role looks like. When I ask them about their biggest pain points, I get insight into where their weaknesses are, and whether I think these are things I want to deal with or tackle.
Asking about biggest pain points is doubly beneficial, though, because then I can also look for things I can relate to. I look for things similar to what I have experienced in the past. When I find them, I can then discuss my own similar experience and what happened in that situation. In doing that, I provide the interviewer with information about how I can help them, how their hiring me will benefit them and make me the best candidate for the position.
Is it possible that I won't find anything I can relate to? I suppose, but I don't think it's all that frequent. If it happens, it may mean that I'm not a good fit for that position anyway.
I also think that to whatever degree I can pull this attitude off, it takes some of the pressure off of me too. I learned many years ago that I interviewed the best when I didn't really *need* the job, likely because I wasn't paralyzed with terror for my job status.
So, take a deep breath, relax, and just chat. Your passion and expertise will come out naturally. :)